Morris tribune. [volume] (Morris, Minn.) 1880-2000, 1887-03-30
PHOTOTYPIC WORK.
SOMETHING ABOUT THE VARIOUS
PROCESSES NOW EMPL DYED.

The Methods of GOupil, in Paris-Ouick-
ness of American Processes-The Ao-
ton of Light Oh Sensitlzed Gelatine.
Photogravure.
The most common forms of reproductive
art nowadays are those based on plotog-
raphy, and it may not be generally known
that the most extensive concern i'll the
country that is devoted to this kind of
work is housed in Brooklyn. TIE conn
pany who controls these works &nh Give
employment to Il considerable number OF
operatives, some of whom are to hc re-
garded as artists rather than mechanics,
for into the finishing and printing OF the
plates taste as we'll rs skill nur: enter.
The house of Goupil, in Paris has until
recent years enjoyed almost II monopoly
of photogravure, and its work has celeb
rity for strength and cleGrneSS. The
Goupil process is a secret, hut it is evil
dent from the length of time taken to
prepare plate, and from the appearance
of sundry lines and markings that would
not commonly show in solar print, that
hand work is nearly as important fac
tor as chemical evolution. The company
here in Brooklyn finishes Il plate in as
many hours as days are taken by the
Goupil firm, and the results are in many
instances surprising. Advances in the
art are still to be made, but there is q
broad foundation to work upward from
There are dozens Of names for what is
substantially the same process-the photo
type, photoprint, mosstype, albertype,
artotype, ichtdruk, hehotype, carbon
print, autoglyph, Ives process, Meiacn-
bach process, photo Autograph, photo
caustic print, photo gelatine print, photo
engraving, zinc etching and photogra-
vure The action of light on sensitized
gelatine or other material is the occasion
of all these forms. Gelatine is made sem
sitive by treatment with bichromate of
potash, which likewise renders it insol-
uble by water, and in this condition it
will take" grease, when that is applied,
but when a gelatine sheet is placed under
a Photographic negative the effect of light
striking through the glass is to close the
pores of the gelatine and harden it, and
where light does not act the gelatine be-
comes soft and absorbent. After the
sheet has received the impress from the
negative a greasy ink will adhere to the
hard portions, while the sponge areas,
being kept moist with water, refuse it.
You apply your ink, lay piece of paper
on it, stamp it, the ink comes off on the
paper and there is your picture-a hello
type, in commercial phrase.
APPLIED TO STONE PRINTING.
This process is much the same as 18th.
ography, but the photographic stone holds
grease only where there are decided lines,
while gelatine receives the impress Of
hundred gradations of light and shade.
Photography is applied to stone printing
where anything is to be represented by
clean masses of black and white, and it is
therefore useful for copying maps, plans,
tracings, ink drawings, designs, miniature
calendars, papers and catalogues, line en-.
cravings, autograph letters, and so on.
In that case paper coated with gelatine is
printed on by negative, as in the cases
of an ordinary photograph, and the grease
taking lines are transferred bodily to the
stone. When the ink lines are transferred
to zinc instead of stone and the exposed
portions of the metal are eaten down by
acid, leaving the lines in relief, plate is
made that is similar to a stereotype, and
this form is commonly used for cheap il
Illustrations in daily papers. A plaster
cast may be taken from O gelatine i'm
press after the lines have set, and from
this may be made metal plate that will
print what are called photo engravings.
For photogravure biehromatized gela-
tine is mixed with sand or emery dust, the
picture is thrown on it from a negative,
the grease taking lines harden, the light
portions are swollen with water and
copper shell is deposited On it as an electro
type. The sand gives grain to the sur
face and holds the ink where it is desir-
able to impart half tint. In the hands
of q skillful printer proof photogravrre
can be made almost as strong as an etch-
ing, as it is easy to wipe out the high
lights until they are represented by the
actual whiteness of the paper that re-
ceives the print, while tones and masses
Of shadow are obtainable by leaving films
of ink of less or greater density on the
metal Enthusiastically Eagle.